JP2005140013A - Rankine cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Rankine cycle device with an operating medium supply system having simple and compact construction for automatically returning an operating medium delivered out of a circulation system into the circulation system in a proper return amount. <P>SOLUTION: The Rankine cycle device 10 comprises a closed operating medium circuit consisting of an evaporator 11, an expansion machine 12, a condenser 13, a closed tank 41 and a water supply pump unit 14. The Rankine cycle device also has a trapping mechanism for trapping the operating medium delivered out of the operating medium circuit, an open tank 32 for storing the operating medium, and a liquid phase operating medium returning device for returning liquid phase operating medium stored in the opening tank to any position of a circuit portion of the operating medium circuit ranging from the outlet of the expansion machine via the condenser to the suction port of the supply pump. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a Rankine cycle device, and more particularly, to a Rankine cycle device that is used as, for example, a vehicle-mounted device that converts exhaust heat energy of a vehicle-mounted engine into mechanical energy and includes a working medium supply system that appropriately copes with leakage of the working medium. .

  Conventionally, a run cycle apparatus is known as a system for converting thermal energy into mechanical work. The Rankine cycle apparatus has a structure in which water as a working medium is circulated in a liquid phase state and a gas phase state in a sealed piping system that forms a circulation system. The Rankine cycle apparatus has a feed water pump unit, an evaporator, an expander, and a condenser, and forms a circulation circuit by piping connecting them.

  FIG. 14 shows a schematic configuration of the Rankine cycle apparatus. In FIG. 14, an on-vehicle Rankine cycle device is assumed, the entire configuration is shown, and the structure and internal state of the condenser are shown.

  In FIG. 14, the Rankine cycle apparatus includes a feed water pump unit 110, an evaporator 111, an expander 107, and a condenser 100. These elements are connected by pipes 108 and 115 to form a circulation circuit. The water (liquid phase) sent out at a predetermined amount per minute through the pipe 115 based on the water supply pump unit 110 is heated by the evaporator 111 and becomes water vapor (gas phase). This water vapor is sent to the expander 107 through the next pipe 115, where an expansion action occurs. Mechanical work is performed by driving a mechanical device (not shown) by the expansion action of water vapor in the expander 107. Thereafter, the expanded water vapor is sent to the condenser 100 through the pipe 108, where it is returned from the water vapor state to the water state. Then, it returns to the feed water pump unit 110 through the piping 115, and is sent out from the feed water pump unit 110 again, and the above operation is repeated. In the above, the evaporator 111 is structured to receive heat from an exhaust pipe extending from the exhaust port of the engine. For example, Patent Document 1 can be cited as a document showing an example of the structure of the Rankine cycle device.

  Next, the structure and operation of the condenser 100 in the in-vehicle Rankine cycle device will be described in detail.

  The condenser 100 of the in-vehicle Rankine cycle device includes a water vapor introduction chamber 101, a water collection chamber 102, and a large number of cooling pipes 103 that connect these two chambers in the vertical direction. In FIG. 14, only one cooling pipe (condensation pipe) 103 is exaggerated. The upper half of the inside of the cooling pipe 103 is water vapor (gas phase portion) 104, and the lower half is water (liquid phase portion) 105. In the portion of the water vapor 104, most of the working medium introduced into the cooling pipe 103 from the water vapor introduction chamber 101 is in a gas phase. In the portion of the water 105, most of the working medium flowing through the cooling pipe 103 is in a liquid phase state (condensed water). The boundary portion (gas-liquid interface) between the water vapor 104 and the water 105 is the liquid surface position 112. A cooling fan 106 is provided behind the cooling pipe 103 (on the right side in FIG. 14) and is driven. The periphery of the cooling fan 106 is surrounded by a shroud 106a. Usually, the operation of the cooling fan 106 is controlled by the electronic control unit based on the water temperature at the outlet of the condenser 100. The cooling pipe 103 is simultaneously blown and cooled by a single cooling fan 106 from its upper end to its lower end.

  The condenser 100 operates as follows. Relatively low temperature steam discharged from the expander 107 in accordance with the operation of the Rankine cycle apparatus is introduced into the steam introduction chamber 101 of the condenser 100 through the low pressure steam pipe 108 and flows into the cooling pipe 103. Cooling air 109 sucked by the cooling fan 106 is supplied to the condenser 100. Strong cooling air acts on the water vapor 104 upstream of the condenser 100, that is, the portion where water vapor and water are mixed in the cooling pipe 103, by the cooling fan 106, and the latent heat released when the water vapor is liquefied is the cooling air. Is effectively recovered. Cooling air from the cooling fan 106 also acts on the water 105 on the downstream side of the condenser 100, that is, the portion where only water is substantially present in the cooling pipe 103. Water condensed in the cooling pipe 103 of the condenser 100 is collected in the water collection chamber 102. Thereafter, as described above, the water is pressurized by the feed water pump unit 110 and supplied to the evaporator 111.

  Originally, it is assumed that the Rankine cycle apparatus is operated in a closed system. That is, the circulation system through which the working medium circulates is ideally a closed system and is formed in a sealed state. Therefore, it is desirable that the working medium circulates in the circulation system without leaking. However, practically, the working medium is discharged out of the system for the following two reasons.

  The first reason is that pressurization is performed at the start of the low temperature state between the feed water pump unit 110, the evaporator 111, and the expander 107, which perform the main work as a Rankine cycle device, and the equal pressure balance is maintained. It collapses and water vapor leaks from the seal part of the expander 107 or the like.

  The second reason is that the working medium that has finished work in the expander 107 is changed from water vapor to water by the condenser 100 and is passed between the condenser 100 and the water tank to prepare for the next work cycle. When the function of holding the liquid level at 100 is provided, water may be discharged from the circulation system.

  In an actual Rankine cycle device, it is necessary to keep the total amount of working medium in the entire circulation system at a constant amount. For this reason, the working medium taken out of the circulation system due to the above-described leakage or discharge must be returned to the circulation system by some method in order to make the total amount constant.

  As described above, there are roughly two methods for returning the working medium leaking out of the circulation system into the circulation system. One method is a method of returning from each of the plurality of leak circuits to the main circuit by direct connection. Another method is a method in which each of the plurality of leak circuits is once received in an open tank and then returned to the main circuit.

  In the former case, for example, it is necessary to insert a pump into each of the plurality of leak circuits and to control the operation thereof relatively accurately in accordance with the leak amount. This complicates the system. On the other hand, in the latter case, when the water once stored in the open tank is automatically returned to the circulation system, it must be returned from the open tank so as to cancel out the leakage amount. Necessary.

  In addition, a method of returning manually separately is also conceivable. In that case, it becomes a very simple system. However, manual replenishment during driving is particularly difficult in vehicles that are running. In addition, the amount of replenishment during travel must be equal to the amount that leaks out of the circulatory system, and in order to cover a sufficient travel distance (time), although it depends on the driving conditions, If a large tank is required and it is assumed that it is mounted on a vehicle, it becomes a factor that hinders downsizing. Therefore, there is a problem in practicality.

  Based on the above, an actual Rankine cycle apparatus has the following three problems. (1) The working medium leaking out of the circulatory system can be automatically returned to the circulatory system, (2) It can be configured sufficiently small on the assumption that it is an in-vehicle device, and (3) The in-vehicle device. It is possible to easily realize the optimum means without using complicated control when it is assumed.

  In Patent Document 2, a mixture composed of oil for lubricating an expander and water mixed therein is supplied to a coalescer-type water separation means, where water is separated from the oil, and the oil from which the water has been separated is supplied to the expander. A Rankine cycle device is disclosed that returns and returns separated water to the circulation circuit. However, the apparatus disclosed in Patent Document 2 does not have a function of maintaining the liquid surface position in the condenser as described in the reason 2 above, so that water is discharged from the circulation system, and thereafter It is not equipped with an open tank for storing water. Therefore, the technique disclosed in Patent Document 2 cannot be applied as it is to a Rankine cycle device including an open tank.

Note that conventional systems similar to the working medium supply system that automatically replenishes the leaked working medium in the Rankine cycle device include, for example, an automobile engine cooling system, a car air conditioner refrigerant supply system, and a thermal power plant ascites And dormant facilities.
JP 2002-115504 A JP 2003-97222 A

  The problems to be solved by the present invention are as follows. In the Rankine cycle device in which the circulation system of the working medium is configured as a closed system, the working medium is circulated in the system while keeping the total amount of the working medium constant. When leakage of the working medium occurs in the circulation system, the leakage amount of the working medium is kept in order to keep the total amount of working medium in the system constant so that the operation of the Rankine cycle device is not hindered by the decrease of the working medium. Is necessary to automatically replenish the system. Further, in the Rankine cycle apparatus configured to maintain the liquid level position of the working medium in the condenser at a constant position, it is necessary to replenish the working medium with a more precise amount of leakage at a more appropriate timing. . In addition, the working medium replenishment supply system of the Rankine cycle apparatus needs to have a simple structure and a compact configuration.

  In view of the above problems, an object of the present invention is to provide a working medium supply system capable of automatically returning a working medium that has left the circulation system to the circulation system at an appropriate timing and with a precise and accurate return amount. It is providing the Rankine-cycle apparatus provided.

  Another object of the present invention is that the condenser is configured so that the liquid level position of the working medium is held at a constant position, and is discharged from the circulation system so that the liquid level position can be accurately maintained. It is an object of the present invention to provide a Rankine cycle device including a working medium supply system capable of automatically returning a working medium to a circulatory system automatically at an appropriate timing and with a precise and accurate return amount.

  Another object of the present invention is a Rankine cycle device installed in a traveling vehicle such as an automobile, which can automatically return a working medium that has come out of the circulation system to the circulation system, and has a simple structure. Another object of the present invention is to provide a Rankine cycle device including a working medium supply system configured in a compact manner.

  The Rankine cycle device according to the present invention is configured as follows in order to achieve the above object.

  The first Rankine cycle device (corresponding to claim 1) has, as a basic configuration, an evaporator that heats the liquid-phase working medium pressurized in the previous stage and converts it into a gas-phase working medium, and an output from the evaporator. An expander that converts thermal energy of the gas phase working medium into mechanical energy, a condenser that cools the gas phase working medium discharged from the outlet of the expander and returns it to the liquid phase working medium, and the condenser discharges A closed working medium circulation circuit comprising a closed tank for storing the liquid phase working medium and a supply pump for pressurizing the liquid phase working medium in the closed tank again and supplying it to the evaporator. The Rankine cycle device further includes a collecting mechanism for collecting the working medium that has flowed out (leaked or discharged) from the working medium circulation circuit, and an open tank for storing the working medium supplied from the collecting mechanism. And the liquid phase working medium stored in the open tank in any of the circuit parts (atmospheric pressure equivalent region) from the outlet of the expander to the inlet of the supply pump via the condenser in the working medium circulation circuit. A liquid-phase working medium returning device for returning to the location.

  In the Rankine cycle device, when the working medium leaks out of the working medium circulation circuit configured as a closed system, for example, the leaked working medium is collected and stored in the open tank. On the other hand, since the total amount of the working medium circulating in the circulation circuit needs to be kept constant, the liquid phase working medium (water) stored in the open tank is a liquid phase working medium return device. The pump returns an appropriate amount at an appropriate timing to any location in the atmospheric pressure equivalent region in the circulation circuit.

  In the above configuration, the second Rankine cycle device (corresponding to claim 2) is preferably attached to a condenser that is controlled so that the liquid level position of the internal liquid phase working medium becomes a predetermined constant position. The liquid-phase working medium discharge unit for discharging the liquid-phase working medium to the outside of the working medium circulation circuit according to the fluctuation of the liquid level position and supplying the liquid-phase working medium to the collecting mechanism is characterized. As a result, in the Rankine cycle device configured so that the liquid level position of the condensed water in the condenser is maintained at a desired constant position, it is possible to appropriately incorporate the leakage-compatible working medium supply system.

  In the third Rankine cycle device (corresponding to claim 3), in the above configuration, preferably, when the liquid level position is below the fixed position, the liquid phase working medium stored in the atmosphere open tank is circulated as a working medium. It is characterized by keeping the liquid level at the above-mentioned fixed position by returning to the circuit.

  In the fourth Rankine cycle device (corresponding to claim 4), in the above configuration, preferably, when the liquid surface position is above a certain position, the liquid phase working medium in the condenser is discharged from the liquid phase working medium discharge unit. It is characterized by keeping the liquid level at a constant position by discharging the liquid and supplying it to the open tank via the collecting mechanism.

  According to the present invention, in the closed system working medium circulation circuit in the Rankine cycle device, the working medium for collecting and storing the working medium leaked or discharged from the circulation circuit and replenishing the lacking working medium to the circulation circuit is provided. The supply system can be realized with an automatic apparatus configuration, and can be configured simply and compactly.

  An air release tank is separately provided for the normal closed tank of the working medium circulation circuit in the Rankine cycle device, and the working medium discharged from the circulation circuit is collected in a liquid phase and stored in the air release tank. The deficient working medium is returned to the region equivalent to the atmospheric pressure from the expander outlet to the suction port of the supply pump including the condenser in the circulation circuit, so that the closed circulation circuit is replenished with the working medium. As a result, the differential pressure between the open air tank and the closed circulation circuit is reduced, and the working medium can be circulated easily and smoothly. This also makes it possible to easily and smoothly adjust the flow rate variation (buffer effect) of the working medium in the closed circulation circuit and recirculate the leaked working medium into the circulation circuit.

  Furthermore, according to this invention, the flow volume fluctuation | variation of the working medium in the closed circuit of a Rankine cycle apparatus can be adjusted. That is, the buffer effect works and can absorb the flow rate fluctuation. The working medium is circulated with reference to the liquid level position of the liquid working medium in the condenser, the proper amount of working medium in the closed circuit is secured by securing the amount of the working working medium by the supply pump, and the gas phase portion of the condenser It is possible to reduce the change in the heat transfer area of the liquid phase part.

  According to the present invention, in the Rankine cycle device that is controlled so that the liquid level position of the liquid phase working medium in the condenser is held at a fixed position, the liquid level working medium is discharged when the liquid level position of the condenser rises from the fixed position. By replenishing the liquid surface position when it drops below a certain position and reducing the fluctuation of the liquid surface position, it is possible to reduce the change in the heat transfer area between the gas phase part and the liquid phase part of the condenser, Cooling can be performed without taking into account the change in the heat transfer area, the control accuracy can be improved, and consumption of excess heat energy during cavitation of the supply pump and reheating in the evaporator can be reduced.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments (examples) of the present invention will be described below with reference to the accompanying drawings.

  First, the configuration of the entire system of the Rankine cycle device according to the present invention will be described with reference to FIG.

  The Rankine cycle apparatus 10 includes an evaporator 11, an expander 12, a condenser 13, and a feed water pump unit 14 including a supply pump. The evaporator 11 is connected to the expander 12 by a pipe 15, the expander 12 is connected to the condenser 13 by a pipe 16, and the condenser 13 to the feed water pump unit 14 is connected by a pipe 17, and the feed water pump unit is connected. 14 to the evaporator 11 are connected by a pipe 18. With such a piping structure or the like, a closed circulation circuit (circulation system) in which the working medium circulates in a liquid phase or gas phase state in the Rankine cycle apparatus 10 is formed. In the Rankine cycle device 10, the working medium is water or steam.

  The circulation circuit of the Rankine cycle apparatus 10 has a circulation structure sealed against the outside where water or water vapor is circulated. In the circulation circuit of the Rankine cycle apparatus 10, water (liquid phase) moves from the liquid surface position indicated by the broken line P <b> 1 in the condenser 13 to the evaporator 11 through the water supply pump unit 14. In FIG. 1, the pipes 17 and 18 related to the water portion are represented by thick solid lines. Further, water vapor (vapor phase) moves from the evaporator 11 through the expander 12 to the liquid level position P1 of the condenser 13. In FIG. 1, the pipes 15 and 16 relating to the water vapor portion are represented by thick broken lines.

  The Rankine cycle apparatus 10 changes the phase of water to water vapor using heat discharged from a heat source, and generates mechanical work using the expansion action of water vapor. The evaporator 11 is a mechanism for changing the phase of water to water vapor. As will be described later, the Rankine cycle device 10 according to this embodiment is configured as an in-vehicle device mounted on an automobile. For this reason, the evaporator 11 uses the heat of the exhaust gas as a heat source. That is, the evaporator 11 uses the heat of the exhaust gas passing through the exhaust pipe 45 of the engine (internal combustion engine) to heat the water supplied from the feed water pump unit 14 and further overheat to raise the temperature and pressure. Generate high-pressure steam. The high-temperature and high-pressure steam generated in the evaporator 11 is supplied to the expander 12. It goes without saying that, regardless of the exhaust pipe 45, the heat of the exhaust gas having a higher temperature such as an exhaust port downstream of the engine exhaust valve or an exhaust manifold (not shown) can be used.

  In the expander 12, the output shaft 12a is connected to a rotor or the like (not shown) of a motor / generator (M / G) 19 and is driven as a generator. The expander 12 has a structure for expanding the high-temperature and high-pressure steam supplied from the evaporator 11, and rotates the output shaft 12a based on the expansion action of the steam. When the output shaft 12a of the expander 12 rotates, the rotor of the motor / generator 19 is rotated to perform a required mechanical rotation operation or power generation operation. Thereby, mechanical work can be performed using the heat of exhaust gas. The output shaft 12a of the expander 12 is also connected to the hydraulic pump 25 to drive it.

  As described above, the expander 12 outputs mechanical work by the expansion action of the high-temperature and high-pressure steam supplied from the evaporator 11 through the pipe 15 to drive each load such as the motor / generator 19 and the hydraulic pump 25. . The water vapor discharged from the expander 12 and lowered in temperature and temperature decreases in temperature and pressure, and is supplied to the condenser 13 via the pipe 16 in this state. The condenser 13 cools and liquefies the water vapor from the expander 12. Water (condensed water) generated by liquefaction in the condenser 13 is returned to the feed water pump unit 14 via the pipe 17. The high-pressure feed water pump 44 of the feed water pump unit 14 pressurizes the condensed water liquefied by the condenser 13 and supplies the condensed water again to the evaporator 11 through the pipe 18.

  The Rankine cycle apparatus 10 having the entire system configuration as described above includes the following elements as other related components.

  A relief valve 22 for adjusting the pressure in the pipe 18 in accordance with the pressure fluctuation in the pipe 18 is attached to the pipe 18 in the vicinity of the evaporator 11. The casing 21 of the expander 12 is provided with a breather (separator) 23 for returning leaked water vapor to the pipe 16. An oil sump 24 is provided at the lower part of the expander 12, and oil mixed with water from the oil sump 24 is passed through a pipe 26 by an oil pump 25 through an oil coalescer 27. Water and oil are separated by the oil coalescer 27, and the water is accommodated in the lower part of the oil tank 28 due to the difference in specific gravity. A valve mechanism 30 that is operated by a float sensor 29 is attached to the oil tank 28. The oil stored in the upper part of the oil tank 28 separated by the oil coalescer 27 is supplied to each part of the expander 12 through the pipe 31 and through an oil passage (not shown) formed in the output shaft 12a. . The water stored in the lower portion of the oil tank 28 is supplied through the pipe 33 to the open tank 32 of the water supply pump unit 14 by the operation of the valve mechanism 30. The open tank 32 is a tank opened to the atmosphere, and stores the working medium leaked (or leaked) or discharged from the circulation circuit in a liquid phase state. A pipe 35 to the condenser 13 is provided from the open tank 32 of the feed water pump unit 14 via a check valve 34. Further, the water in the open tank 32 may be provided to the pipe 16 by providing the pipe 35a. The condenser 13 is provided with a liquid level sensor 38 and an air vent 39 in the vicinity of the liquid level position. Water supply from the open tank 32 to the condenser 13 is performed by a return pump 37 driven by a motor 36 that is turned on and off by a signal from a liquid level sensor 38. Further, the condenser 13 is provided with a pipe 40 for draining to the open tank 32 through the air vent 39. The pipe 17 for returning the condensed water discharged from the condenser 13 is connected to a water coalescer 42 in the sealed tank 41 of the water supply pump unit 14. The water in the sealed tank 41 is supplied to the evaporator 11 through the pipe 18 by a high-pressure feed water pump 44 operated by a motor 43. Furthermore, the condenser 13 is provided with a plurality of cooling fans 46, 47, and 48 for generating cooling air independently depending on the location.

  In the above configuration, the working medium supply device is configured by the device portion related to the lower portion from the liquid level position inside the condenser 13 and the feed water pump unit 14. In the circulating system of the sealed working medium in the Rankine cycle device 10, the working medium leaked from the breather 23 of the expander 12 is returned to the pipe 16 via the outlet P2, and returned to the circulating system.

  FIG. 2 is a configuration diagram showing a specific structure of the water supply pump unit 14 described above. The water supply pump unit 14 includes a water coalescer 42, a sealed tank 41, a high-pressure water supply pump 44 operated by a drive motor 43, an open tank 32, a return pump 37, and a check valve 34. In FIG. 2, the rotation shaft 49 of the drive motor 43 is shown in parallel with the paper surface. However, this is for convenience of explanation, and in actuality, the rotation shaft 49 is arranged so as to be perpendicular to the paper surface. Yes. A cam mechanism 49a is engaged with the rotation shaft 49 of the drive motor 43 to form a cam shaft.

  In the above, the water coalescer 42 performs oil separation. The sealed tank 41 directly collects leaked water from the high-pressure feed pump 44. The high-pressure feed water pump 44 supplies the required amount of water by controlling it according to the pump speed. The open tank 32 is for temporarily storing leaked water leaking outside the circulation circuit. The return pump 37 returns the leaked water to the sealed tank 41 or returns the water to the subcooler of the condenser 13. That is, the return pump 37 returns the leaked water from the open tank 32 to the sealed tank 41 through the pipe 152 provided with the check valve 151, and supercools the condenser 13 through the pipe 35 provided with the check valve 34 as necessary. Send water to the vessel. The check valve 151 in the pipe 152 prevents backflow from the closed tank 41, and the check valve 34 in the pipe 35 prevents backflow from the subcooler of the condenser 13. Water from the outlet 13 a of the condenser 13 enters the high-pressure feed water pump 44 driven by the drive motor 43 through the pipe 17. The high-pressure feed pump 44 sends water to the evaporator 11 through the pipe 18. In addition, leaked water is returned to the open tank 32 by the pipe 40.

  Next, the configuration of supply of the working medium for leakage in the Rankine cycle device 10 will be described in detail.

  In the Rankine cycle device 10, in the circulation circuit for circulating the working medium, the liquid phase working medium leaked or discharged at several places as described above is collected (oil coalescer 27, oil tank 28, valve mechanism 30. , Piping 33, piping 40, etc.), and then collected in the open tank 32 and stored here. The water (liquid phase working medium) stored in the open tank 32 is preferably a circuit portion between the steam outlet 53 of the expander 12 and the inlet of the high-pressure feed water pump 44 via the condenser 13 ( It is automatically returned to any point in the atmospheric pressure equivalent region). For example, as described above, the water stored in the open tank 32 is returned to the supercooler of the condenser 13 by the return pump 37 and the pipe 35 as described above. Further, the return of the water stored in the open tank 32 to the circulation circuit may be performed by using the return pump 37 and returning it to the pipe 16 through the pipe 35 a formed by extending the pipe 35. Thus, the working medium leaking from the circulation circuit of the Rankine cycle device 10 is automatically returned to the circuit portion in the atmospheric pressure equivalent region of the circulation circuit at an appropriate timing, and the total amount of the working medium in the circulation circuit is kept constant. Is done.

  In the Rankine cycle device 10 described above, the function of absorbing flow rate fluctuations of the working medium and the working medium discharged or leaked outside the circulating circuit with respect to the circulating circuit in which the liquid-phase or gas-phase working medium circulates. It also has a function to automatically return to the circulation circuit. In particular, in the present embodiment, the condenser 13 causes the liquid-phase working medium to be closed in the Rankine cycle device 10 based on the liquid level position that forms the interface between the gas-phase working medium and the liquid-phase working medium existing in the condenser 13. Liquid phase working medium discharge device that discharges outside and stores it in the open air tank 32, that is, an air vent 39, and a liquid phase working medium supply that circulates the liquid phase working medium stored in the open tank 32 in the closed circuit of the Rankine cycle device 10. A device or return pump 37 is provided.

  And when the said liquid level position is below a predetermined fixed position, the water stored in the open tank 32 is returned into the closed circuit of the Rankine cycle device 10, and the said liquid level position is above the predetermined fixed position. At this time, the water (condensed water) in the condenser 13 is discharged to the open tank 32, and thereby the liquid level is held at a predetermined fixed position.

  Furthermore, in the configuration according to the present embodiment, the amount of supply of the working medium in the circulation system to the evaporator 11 varies greatly, and the high-pressure feed pump 44 follows the variation in seconds. Accordingly, a difference occurs in the inflow / outflow flow rate of the condenser 13 and the holding amount of the working medium in the circulation system varies significantly. Therefore, in order to stabilize the condensation performance, the working medium is positively discharged from the circulation system. Or actively return to the circulatory system. In this case, as described above, the return position of the working medium is set at any point between “expander outlet”-“condenser”-“high-pressure feed pump inlet (sealed tank)”. However, in the present embodiment, all of these locations are at a slightly higher pressure than the atmospheric pressure, so that they are collected and stored in the atmosphere release tank 32 together with the leaked working medium and then actively performed. Is required.

  A specific configuration example of this embodiment will be described. In the first configuration example, as described above, the liquid level working medium (water) collected and stored in the open tank 32 is constant in the liquid level position of the condenser 13 using one return pump 37 and the liquid level sensor 38. The liquid-phase working medium is actively and automatically returned to the system by replenishing it to the position. In this case, for example, when the pressure in the condenser 13 is always controlled to a weak positive pressure, the liquid phase working medium is removed from the open tank 32 by the above-mentioned “expander outlet”-“condenser”-“high-pressure feed pump”. At least one return pump is required to automatically return to somewhere between the “inlet (sealed tank)”. In the present embodiment, the air that has entered the circulation system is applied to a configuration in which the pressure inside the condenser is set to a weak positive pressure and is discharged to the outside of the circulation system using the air vent 39, and is discharged from the air vent 39 to the open tank 32. The liquid phase working medium is returned to the circulation system by using a return pump 37 via a pipe 35 and a pipe 35a different from this.

  According to the above configuration, in the Rankine cycle apparatus 10 that has been operated while circulating the working medium in the circulation circuit in a certain steady state, the heat load suddenly decreases, the discharge amount of the high-pressure feed water pump 44 decreases, and the condenser 13 When the outflow amount becomes smaller than the inflow amount, the level of the condensed water in the condenser 13 gradually rises. However, when the liquid level in the condenser 13 becomes equal to or higher than the set position based on the air vent 39, the condensed water passes through the air vent 39 and exits the circulation system in the form of water. Can be stored and once stored, so that flow fluctuations can be absorbed. On the other hand, when the heat load suddenly increases and the outflow amount becomes larger than the inflow amount into the condenser 13, the liquid surface position gradually decreases. However, water is returned from the open tank 32 to the supercooling section in the condenser 13 so as to cancel out this by the motor 36 and the return pump 37 that are operated by the detection signal of the liquid level sensor 38. Thereby, the flow fluctuation in the circulation circuit can be absorbed. A signal for starting / stopping the return pump 37 is given by a liquid level sensor 38. Leakage from the expander 12 is collected in the open tank 32 via the collecting mechanism and then returned to the circulation system via the return pump 37.

  The second configuration example is to make the internal pressure of the condenser 13 a weak negative pressure only when returning the working medium into the circulation system. Thereby, the water stored in the open tank 32 outside the circulation system can be passively returned to any location between the “expander outlet”-“condenser”-“high-pressure feed water pump (sealed tank)”. It becomes possible. According to this configuration example, the return pump 37 can be omitted.

  2, in the case of the feed pump unit 14, the return destination of the return pump 37 is the header tank or the pipe 16 below the supercooler via the pipes 35 and 35 a. And the example which returns directly to the airtight tank 41 via the piping 152 is shown. The water supply pump unit 14 has or can have the following characteristic points from the viewpoint of practical design.

(1) An open tank 32 is arranged around the sealed tank 41 for miniaturization.
(2) The liquid level position of the open tank 32 is arranged so that the difference in distance from the liquid level of the condenser 13 is small.
(3) In order to reduce the size of the return pump 37, it is desirable to minimize the pipe length and to minimize the difference between the liquid level in the condenser 13 and the liquid level in the open tank 32. Therefore, an arrangement in which the upper part is a sealed tank 41 and the lower part is an open tank 32 is also conceivable.
(4) In the sealed tank 41, a water coalescer 42 for separating the mixed oil is separated.
(5) A high-pressure water supply pump 44 is also built in the sealed tank 41 to maximize self-priming and to attenuate generated sound.
(6) The return pump 37 is replaced with a high-pressure feed pump 44 by a circuit switching valve in the case of an emergency in which the evaporator 11 becomes abnormally hot when the amount of feed water decreases due to a trouble with the high-pressure feed pump 44 or the like. The return pump 37 switches the discharge side to the main circuit side, protects the evaporator 11 by restraining it within the allowable heat resistance range, and temporarily maintains the operation of the Rankine cycle device to prevent the occurrence of a sudden stop, It has functions such as maintaining the entire system by gradually stopping it.

  Next, with reference to FIG. 3 and FIG. 4, the structural example when said Rankine-cycle apparatus 10 is mounted in a vehicle is demonstrated.

  In the configuration example shown in FIG. 3, 201 indicates the contour of the body shape of the front portion of the vehicle, and 202 indicates the front wheels. The inside of the body 201 is an engine room 203, and the engine 50 is mounted in the engine room 203. An exhaust manifold 51 is provided on the back side of the engine 50, and the exhaust pipe 45 described above is connected to the exhaust manifold 51. The evaporator 11 is provided at a location near the exhaust manifold 51 in the exhaust pipe 45. A pipe 18 from the high-pressure feed pump 44 is connected to the evaporator 11. The pipe 18 supplies water to the evaporator 11 using the heat of the exhaust gas discharged from the exhaust manifold 51 as a heat source. The evaporator 11 phase-converts water into steam with the heat of the exhaust gas, and supplies the steam to the expander 12 through a pipe 15 connected to the steam inlet 52 of the expander 12. The expander 12 converts the expansion energy of water vapor into mechanical energy.

  The steam outlet 53 of the expander 12 is connected to the pipe 16. A condenser 13 that cools and condenses water vapor to form a liquid is disposed between the pipe 16 and the sealed tank 41 that leads to the inlet side of the high-pressure feed water pump 44. The condenser 13 is located in front of the front part of the vehicle. 3 and 4, in addition, the layout of the open tank 32, the water coalescer 42, the return pump 37, the oil coalescer 27, the supercooler (liquid phase part of the condenser 13) 54, the air vent 39, the check valve 34, and the like. The state is shown. The high-pressure feed water pump 44, the evaporator 11, the expander 12, the condenser 13 and the like constitute a Rankine cycle device that converts thermal energy into mechanical energy as described above.

  4, the circuit switching valve 210 is provided after the check valve 34 from the left in FIG. 4, and the other end of the circuit switching valve 210 is connected to the pipe 18. One end of 211 is connected. With this configuration, when a trouble occurs in the high-pressure feed pump 44 and the amount of feed water decreases, or when the evaporator 11 becomes unexpectedly hot, the circuit switching valve 210 switches to the high-pressure feed pump 44 side. The discharge side of the return pump 37 is switched to the main circuit side, the evaporator 11 is protected from instantaneous abnormal overheating, and the operation of the Rankine cycle device is temporarily continued to prevent a sudden stop and the like, and gradually stop. It has a function to maintain the entire system.

  Next, the operation of the Rankine cycle device will be described along the flow of water and water vapor.

  The water cooled and condensed by the condenser 13 is pressurized by the high-pressure feed water pump 44 and supplied to the evaporator 11 through the pipe 18.

  Water, which is a liquid phase working medium, is heated by adding heat energy in the evaporator 11, further heated to high temperature / high pressure steam that has been heated and pressurized, and is supplied to the expander 12. The expander 12 converts thermal energy into mechanical energy by the expansion action of the high-temperature and high-pressure steam whose temperature has been increased. Thereby, the motor / generator 19 attached to the expander 12 obtains mechanical energy.

  The water vapor that has flowed out of the expander 12 becomes water vapor whose temperature has been lowered and reduced, and flows into the condenser 13. The temperature-decreased water vapor that has flowed into the condenser 13 is cooled and condensed again, and is then supplied to the high-pressure feed pump 44 through the water coalescer 42 as condensed water. Thereafter, the water that is the working medium repeats the above circulation, and continues to supply the high-temperature and high-pressure water vapor that has been heated and pressurized to the expander 12.

  Next, control of the liquid surface position of the condenser 13 in the Rankine cycle device 10 will be described with reference to FIGS.

  FIG. 5 shows the system of the Rankine cycle apparatus 10 with the condenser 13 as the center, and the condenser 13 is drawn as a front view as seen from the front side of the vehicle. FIG. 5 shows the state of the working medium inside the condenser 13 (water (condensed water): W1, water vapor: W2). FIG. 6 is a side view of the condenser showing the positional relationship of the cooling fans 46, 47, and 48 in the condenser 13, and the internal state is also shown.

  The condenser 13 includes a steam introduction chamber 13A at the upper end, a water collection chamber 13B at the lower end, and an intermediate chamber 56 at the center. A plurality of cooling pipes 55 are provided between the steam introduction chamber 13A and the intermediate chamber 56, and between the intermediate chamber 56 and the water collection chamber 13B, and the respective chambers are in communication with each other. Cooling fins 55 a are provided around the cooling pipe 55.

  The steam introduction chamber 13 </ b> A of the condenser 13 is connected to the steam outlet 53 of the expander 12 through the pipe 16. The water collection chamber 13B of the condenser 13 is connected to the water supply pump unit 14 via a pipe 17 and the like. As described above, the expander 12 is connected to the evaporator 11 via the pipe 15, and similarly, the feed water pump unit 14 is connected to the evaporator 11 via the pipe 18. The evaporator 11 receives heat 50 </ b> A from the exhaust gas of the engine (heat source) 50 through the exhaust pipe 45. In the water supply pump unit 14, components such as the sealed tank 41, the water coalescer 42, the high-pressure water supply pump 44, the drive motor 43, the open tank 32, the return pump 37, and the motor 36 are shown.

  In the condenser 13, the water vapor W2 is cooled and condensed to become water (condensed water) W1. A horizontal line 65 shown in the intermediate chamber 56 indicates the liquid level of the water W1. A liquid level sensor 38 and an intermediate drain port 59 are provided at required positions corresponding to the position of the liquid level 65 in the intermediate chamber 56. A detection signal related to the liquid level position output from the liquid level sensor 38 is sent to the control device 60. The control device 60 generates a motor control command signal based on the liquid level position detection signal, and gives this motor control command signal to the motor 36 of the return pump 37. On the other hand, an air vent 39 for water vapor is connected to the intermediate drain 59. The outlet side of the air vent 39 communicates with the open tank 32 via a pipe 40 having a check valve 58. An exhaust pump 57 is attached to the pipe 40 in parallel.

  Further, in the condenser 13, as shown in FIG. 6, a cooling fan 46 is disposed on the back side of the condenser 13 corresponding to the area where the water vapor W2 exists, and the cooling fan 47, corresponding to the area where the water W1 exists. 48 is arranged. The cooling operation of the cooling fan 46 is controlled by the pressure control device 62 based on, for example, a water vapor pressure detection signal of a pressure sensor 61 attached to the pipe 16 to which the water vapor W2 is supplied. The cooling fan 46 is a condensing cooling fan used for steam pressure adjustment. The cooling operation of the cooling fans 47 and 48 is controlled by the temperature control device 64 based on, for example, a water temperature detection signal of the temperature sensor 63 attached to the pipe 17 through which the water W1 flows. The cooling fans 47 and 48 are water cooling cooling fans for cooling the condensed water. In FIG. 6, A1 indicates the flow of cooling air from the front based on the rotation operation of the cooling fan 46, and A2 indicates the flow of cooling air from the front based on the rotation operation of the cooling fans 47 and 48. As described above, in the condenser 13, the cooling of the gas phase part (steam condensing part) 70, which is an equipment part corresponding to the water vapor W2, and the liquid phase part (condensed water cooling part), which is an equipment part corresponding to the water W1. The cooling of 71 is performed independently.

  In said structure, the water vapor | steam which comes out from the steam outlet 53 of the expander 12 is equivalent to atmospheric pressure. In the intermediate chamber 56 which is an outlet collection portion of each of the upper cooling pipes (condensation pipes) 55, water is discharged from the air vent 39 in order to adjust the liquid level 65 to be located in this space. The high-pressure feed water pump 44 serves as a feed pump for the main circulation circuit of the Rankine cycle apparatus 10 and sends a required amount of water to the evaporator 11.

  Further, in the above configuration, the reserve open tank 32 is open to the atmosphere, and reserve water is reserved for reserve in a closed circulation circuit in the system. The return pump 37 receives the signal from the liquid level sensor 38 and supplies water into the condenser 13. The exhaust pump 57 sucks the downstream side of the air vent 39 when the condenser 13 is operated at a negative pressure.

  The operation of the exhaust pump 57 is performed by sensing the negative pressure with the pressure sensor 61 and the pressure control device 62 shown in FIG. 6, or the liquid level 65 is detected by the liquid level sensor 38. It can be configured to sense when the position exceeds the upper limit of the predetermined range and operate by the control device 60.

  Further, the exhaust check valve 58 prevents the backflow of the atmosphere when the inside of the condenser 13 becomes a negative pressure. The check valve 34 prevents a back flow of the return pump 37. The water vapor air vent 39 allows water and air to pass but does not pass water vapor. The intermediate drain port 59 is for restricting the change in the position of the liquid level 65 of the condensed water due to discharge of noncondensable gas and overflow of the water so that the liquid level position varies within a predetermined range. The liquid level sensor 38 outputs a position signal related to the liquid level 65 to the control device 60. The control device 60 controls the operation of the return pump 37 so that the position of the liquid level 65 exists in the intermediate chamber 56. The position of the liquid level 65 is controlled to be a height position included in a range between the air vent 39 and the liquid level sensor 38. For the liquid level sensor 38, for example, a capacitance type level sensor or a float type level switch is used.

  The pressure sensor 61 detects the pressure inside the condenser 13, and basically detects the pressure of the water vapor W2. The pressure control device 62 operates the cooling fan 46 so that the internal pressure of the condenser 13 becomes a set value. The temperature sensor 63 detects the temperature of the condensed water W1. The temperature control device 64 operates the cooling fans 47 and 48 so that the condensed water temperature becomes a set value.

  The structure and operation of the air vent 39 will be described in detail with reference to FIGS. 7 and 8 show a state when the air vent 39 is closed, FIG. 7 is a longitudinal sectional view, and FIG. 8 is a sectional view taken along line AA in FIG. FIG. 9 is a longitudinal sectional view showing a state when the air vent is open. In FIG. 7 and the like, the left side of the air vent 39 is the condenser side, and the right side is the atmosphere side. The air vent 39 is sealed when the interior is filled with saturated water vapor (FIG. 7), and is automatically opened when non-condensable gas such as water or air is present to discharge water or non-condensable gas. Seal again (FIG. 9).

  The air vent 39 includes a valve 66 disposed at a central position of the container, a valve support 67 that supports the valve 66, and a valve opening (packing) 68. The valve 66 supported by the valve support 67 is arranged in a positional relationship capable of closing the valve port 68. The valve 66 is formed by combining two diaphragms 66a so as to form a sealed space, and a thermo liquid (temperature sensitive liquid) 69 is accommodated in the sealed space inside. The thermo liquid 69 has a characteristic that, like water, it is liquid under a certain pressure and below a certain temperature and expands as a gas when exceeding a certain temperature. FIG. 10 shows a saturation curve C1 of thermolyd and a saturation curve C2 of water. Since the temperature at which the thermo liquid 69 becomes gas is lower than the temperature at which water becomes steam by ΔT (about 10 ° C.), the thermo liquid 69 is vaporized and vaporized when the inside of the air vent 39 is an atmosphere of water vapor W2. The sealed space containing the expanded thermo liquid 69 pushes the diaphragms 66a on both sides outward, and closes the gap between the valve 66 and the valve port 68 formed by the diaphragm 66a (FIG. 7). Conversely, when the inside is at a low temperature (the surrounding environment is a non-condensable gas A3 such as air), the thermo liquid 69 is in a liquid state, the diaphragm 66a contracts inward, and the valve 66 and the valve port Air or the like is discharged from the gaps 68 (FIG. 9).

  In the above configuration, the control device 60 controls the position of the liquid surface 65 in the condenser 13 that is cooled by the cooling fan 46 and returns the water vapor W2 to the water (condensed water) W1 so as to change within a predetermined range. It is a control device. Based on the detection signal from the liquid level sensor 38 that detects the position of the liquid level 65 that is the boundary between the gas phase part 70 and the liquid phase part 71 in the condenser 13, the control device 60 is lower than the lower limit of the predetermined range. When it drops, the operation of the motor 36 of the return pump 37 that supplies water into the condenser 13 is controlled, and the insufficient amount of water is replenished from the open tank 32 through the pipe 35. Further, when the position of the liquid surface 65 of the liquid phase portion 71 exceeds the upper limit of the predetermined range, the excess water is discharged to the open tank 32 by the intermediate drain 59 and the air vent 39 and the like. Thus, a desirable predetermined range of the position of the liquid level 65 is set by a range determined by the lower limit based on the liquid level sensor 38 and the upper limit based on the air vent 39.

  This will be described in more detail. An intermediate drain port 59 for draining water (condensed water) W1 is installed in the intermediate chamber 56 of the condenser 13 to regulate the upper limit position of the liquid level 65. When the liquid level 65 rises above the intermediate drainage port 59, the position of the liquid level 65 is lowered by causing water to overflow from the intermediate drainage port 59 to the reserve open tank 32. When the liquid level 65 is located below the intermediate drainage port 59, an air vent 39 is installed at the intermediate drainage port 59 so that water vapor is not discharged from the intermediate drainage port 59. As shown in FIGS. 7 to 9, the air vent 39 for preventing the discharge of water vapor is automatically closed when water vapor is present inside, and air (non-condensable gas) or water is present inside. Sometimes the valve opens automatically. Further, a liquid level sensor 38 is disposed below the intermediate drain 59, and when the liquid level 65 is lower than the liquid level sensor 38, water is supplied from the open tank 32 by the return pump 37 and the liquid level 65 is supplied. Is raised to the position of the liquid level sensor 38. Based on the above action, the position of the liquid level 65 is always maintained within the range between the intermediate drain 59 and the liquid level sensor 38. When the interval between the intermediate drain 59 and the liquid level sensor 38 is increased, the error in the heat transfer area between the water vapor W2 side and the water (condensed water) W1 side increases. On the contrary, when the interval becomes small, the operations of the return pump 37 and the air vent 39 frequently occur. Therefore, the distance between the intermediate drain 59 and the liquid level sensor 38 may be set in a range where both of these two effects are reduced. If the main point is to make the heat transfer area constant, the interval is infinitely small and preferably zero.

  FIG. 11 shows details of the position setting of the liquid level 65. 11A shows the positional relationship among the liquid level sensor 38, the air vent 39, and the liquid level 65, and FIG. 11B shows the relationship between the liquid level position, the operation of the air vent, and the operation of the return pump. .

In FIG. 11A, H _A is set as the upper limit liquid level position, H _B is set as the lower limit liquid level position, and H _L is set as the liquid level position 65. When the position _HL of the liquid level 65 is higher than the upper limit liquid level position _HA , the air vent 39 is in an open state and the return pump 37 is off (OFF). Position H _L of the liquid level 65, when located between the upper liquid surface position H _A and the lower limit liquid level position H _B is the air vent 39 is closed, the return pump 37 is off. When the position _{H L} of the liquid level 65 is lower than the lower limit liquid level position _{H B} is the air vent 39 is closed, the return pump 37 is turned on (ON). Thus, variation of the liquid level 65 is suppressed to the upper limit liquid level position in the range of H _A and the lower limit liquid level position H _B.

  In addition, when the Rankine cycle apparatus 10 is started / stopped or transiently changed, the amount of water vapor (mass flow rate) or the amount of drainage (mass flow rate) from the condenser 13 to the high-pressure feed water pump 44 changes. The fluctuation | variation of the position of the liquid level 65 inside can be suppressed, and the operation | movement of the condenser 13 can be performed stably.

  Further, as shown in FIG. 5, apart from the sealed main circuit of the Rankine cycle apparatus 10, a reserve open tank 32 for release to the atmosphere is provided. The open tank 32 is connected to the condenser 13 through an air vent 39 connected to the intermediate drain 59 and a check valve 58. The lower part of the open tank 32 is connected to the outlet 13 a of the condenser 13 via a return pump 37, a pipe 35 and a check valve 34. When the liquid level 65 is higher than the intermediate drain 59, the water overflows into the open tank 32, and when the liquid level 65 is lower than the liquid level sensor 38, the return pump 37 is operated to replenish the water. When the return pump 37 is activated, the liquid level 65 rises due to the supply of water into the condenser 13, and the return pump 37 stops at the position of the liquid level sensor 38. Further, since an intermediate chamber 56 is provided in a region including the intermediate drain port 59 and the liquid level sensor 38 and a plurality of cooling pipes (condensation pipes) 55 are gathered, the drain pump 59 or the return pump 37 is drained from the intermediate drain port 59. It is possible to improve and stabilize the responsiveness of the change in the liquid level 65 when water is supplied. Note that it is only necessary that each cooling pipe (condensation pipe) 55 is connected to the intermediate chamber 56 portion on the steam introduction chamber 13A side and the water collection chamber 13B side, and the provision of the intermediate chamber 56 is not essential.

  Next, the flow of the liquid surface position control performed in the control device 60 will be described with reference to the flowchart of FIG.

First, the position _HL of the liquid level 65 is read by the liquid level sensor 38 (step S10). It is determined whether or not the liquid level position H _L is higher than the upper limit liquid level position H _A (step S11). If the liquid level position H _L is higher than the upper limit liquid level position _HA , the air vent 39 is opened and drained, and the liquid level 65 is lowered (step S12). Thereafter, the process returns to step S10 and returns to step S10. If the liquid level position _HL is equal to or lower than the upper limit liquid level position _HA , the air vent 39 is closed (step S13). The next step, whether the liquid surface position H _L is lower than the lower limit liquid level position H _B is determined (step S14). If and when the liquid level position H _L is lower than the lower limit liquid level position H _B is the return pump 37 is turned on, water is supplied (step S15). If and when the liquid level position H _L is equal to or greater than the lower limit liquid level position H _B is the return pump 37 is turned off, supply of water is not performed (step S16). Thereafter, the process returns to step S10 and returns to step S10.

  FIG. 13 is a graph showing changes in vehicle speed, engine output change, water supply flow rate to the evaporator, and change in the liquid level position of the condenser of a vehicle equipped with the Rankine cycle device 10 according to the present embodiment. 13A shows the change in the vehicle speed, FIG. 13B shows the change in the engine output, FIG. 13C shows the change in the evaporator feed water flow rate, and FIG. 13D shows the liquid level position in the conventional condenser shown in FIG. Show each change. In FIG. 13, the horizontal axis represents time. When the vehicle on which the Rankine cycle device is mounted changes the vehicle speed as shown in FIG. 13 (A), the engine output changes as shown in FIG. 13 (B), and as shown in FIG. 13 (C). Thus, a change in the feed water flow rate to the evaporator 111 occurs, and the liquid level position 112 of the condenser 100 changes as shown in FIG. In other words, on the lateral time axis, when the vehicle starts at times t1, t3, and t5 and stops at times t2, t4, and t6, the engine output changes as the vehicle starts and stops, evaporating The feed water flow rate to the condenser 111 also changes, and the liquid level position 112 of the condenser 100 changes.

As described above, in the on-vehicle Rankine cycle condenser 100, as shown in FIG. 13A, when the vehicle starts / stops or when the vehicle speed changes transiently, the engine output as shown in FIG. 13B. Therefore, the feed water flow rate to the evaporator 111 changes, and the liquid level position 112 in the cooling pipe 103 of the condenser 100 changes. That is, in the condenser 100, when the inflow amount of water vapor is larger than the drainage amount of condensed water, the liquid level position 112 rises, and when the inflow amount of water vapor is less than the drainage amount of condensed water, the liquid level position 112 decreases. It will be. The figure relating to the change in the liquid surface position shown in FIG. 13E is a diagram for the condenser of the present invention. When the vehicle changes the vehicle speed as shown in FIG. 13A, the Rankine cycle device 10 controls the liquid level position as described above, so the liquid level position is determined when the vehicle starts and stops. is only variations between the upper limit position H _a and the lower limit position H _B, large variation does not occur.

  As described above, by suppressing the position fluctuation of the liquid level 65 of the condensed water W1 in the condenser 13 to a predetermined range, the vapor phase portion corresponding to the water vapor and the liquid phase portion corresponding to the condensed water in the condenser 13 are reduced. The change in the heat transfer area is reduced, cooling can be performed without considering the change in the heat transfer area, the control accuracy is improved, and the cavitation in the pump device and the reheating in the evaporator 11 are reduced. Therefore, the liquid surface position control device for the condenser 13 that reduces the consumption of excess heat energy can be obtained.

  In addition, the change width of the heat transfer area can be maintained within an allowable range, and the switching operation of discharging the liquid phase working medium and replenishing supply can be provided with hysteresis, thereby reducing the frequency of the switching operation and condensing. As the operation of the vessel is stabilized, the durability of the device for discharging and replenishing is improved. Furthermore, since the discharge of the gas phase working medium (water vapor) is prevented while the liquid phase working medium (water) is discharged and the set liquid level is appropriately controlled, the operation of the condenser can be stabilized. In addition, the liquid phase working medium can be replenished and supplied to the set liquid level directly from the open reservoir for storing the liquid phase working medium via the return pump. The liquid level position can be stabilized accurately at an early stage by highly accurate supply amount control. Furthermore, the liquid surface position can be controlled while maintaining the total mass flow rate of the working medium in the circulation circuit, and there is no need to add a special device for discharging the working medium to the outside and replenishing from the outside. Can be configured. Furthermore, it is possible to reduce the variation of the liquid level position for each cooling pipe of the condenser, and to stabilize the liquid level quickly and accurately at the time of draining and replenishing the liquid phase working medium, thereby stabilizing the operation of the condenser. It can be carried out.

  The present invention is an on-vehicle Rankine cycle device that collects the working medium leaking from the circulation system, stores it in the atmosphere open tank, and returns it to the circulation system to hold the total amount of working medium. Further, the liquid level in the condenser In a configuration in which the position is held at a fixed position, it is used as a device that optimally returns the liquid phase working medium to the circulation system.

It is a lineblock diagram showing the whole Rankine cycle device system concerning the present invention. It is a fragmentary sectional side view which shows the internal structure of the water supply pump unit which concerns on this embodiment. It is a figure which shows the example of arrangement | positioning structure when the Rankine-cycle apparatus which concerns on this invention is mounted in a vehicle. It is a figure which shows the other structural example when the Rankine-cycle apparatus which concerns on this invention is mounted in a vehicle. It is a system block diagram which shows the flow of the working medium of a Rankine cycle apparatus. It is a side view which shows the internal structure of the part of a condenser, and a peripheral device. It is sectional drawing which shows a structure when the air vent is closed. It is the sectional view on the AA line in FIG. It is sectional drawing which shows a structure when the air vent is open. It is a graph which shows the saturation curve of a thermo liquid and water. It is a figure for demonstrating the detail of a liquid level position setting. It is a flowchart which shows the operation | movement flow of the liquid level position control apparatus of a condenser. It is a timing chart which shows the change of the vehicle speed change of the vehicle carrying the Rankine-cycle apparatus based on this invention, an engine output change, the feed water flow volume to an evaporator, and the liquid level position of a condenser. It is the schematic diagram which showed the conventional vehicle-mounted Rankine-cycle apparatus simply.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rankine cycle apparatus 11 Evaporator 12 Expander 13 Condenser 14 Water supply pump unit 15 Piping 16 Piping 17 Piping 18 Piping 26 Piping 32 Open tank 37 Return pump 38 Liquid level sensor 39 Air vent 41 Sealed tank 42 Water coalescer 43 Motor 44 High pressure water supply Pump 45 Exhaust pipe 46, 47, 48 Cooling fan

Claims (4)

An evaporator that heats the pressurized liquid-phase working medium to convert it into a gas-phase working medium, an expander that converts the thermal energy of the gas-phase working medium into mechanical energy, and an exhaust gas discharged from the outlet of the expander A condenser that cools the gas-phase working medium back to the liquid-phase working medium, a sealed tank that stores the liquid-phase working medium discharged from the condenser, and pressurizes the liquid-phase working medium in the sealed tank again to evaporate the liquid-phase working medium. In a Rankine cycle device having a closed working medium circulation circuit consisting of a supply pump for feeding to the vessel,
A collecting means for collecting the working medium that has come out of the working medium circulation circuit;
An open tank for storing the working medium supplied from the collecting means;
The liquid phase working medium stored in the open tank is located anywhere in the circuit portion from the outlet of the expander in the working medium circulation circuit to the inlet of the supply pump via the condenser. Liquid phase working medium return means for returning to
A Rankine cycle device comprising:   The liquid phase working medium is attached to the condenser which is controlled so that the liquid level position of the internal liquid phase working medium becomes a constant position, and the liquid phase working medium is moved outside the working medium circulation circuit according to the fluctuation of the liquid level position. 2. The Rankine cycle apparatus according to claim 1, further comprising a liquid phase working medium discharging unit that discharges and supplies the collecting unit with the liquid phase working medium.   When the liquid level position is below the fixed position, the liquid level working medium stored in the open tank is returned to the working medium circulation circuit to keep the liquid level position at the fixed position. The Rankine cycle apparatus according to claim 2. When the liquid level is above the fixed position, the liquid phase working medium in the condenser is discharged by the liquid phase working medium discharge means and supplied to the open tank via the collecting means. Thus, the Rankine cycle apparatus according to any one of claims 2 to 3, wherein the liquid level position is maintained at the fixed position.

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